1. Field of the Invention
The present invention generally relates to blood separation apparatus and, more particularly, to those apparatus adapted to utilize containers of whole blood fabricated of vinyl or related resilient material.
2. Prior Art
It has long been known that substantial benefits can occur through the use of various elements of whole blood. The separation of plasma, white cells, red cells, platelets, etc., from a whole blood solution provides a variety of uses which are well known throughout the field of medicine. The methods used by the devices taught by the prior art are not precise in that substantial quantities of the elements sought to be obtained are lost as a result of the inability of sufficiently isolate and subsequently separate the blood elements. A conventional method taught by the prior art utilizes a centrifuge to temporarily isolate the elements utilizing the elements quantitative difference in mass. For example, subjecting a packet of whole blood to centrifugal force will isolate the red cells from the remaining suspended elements as a result of their greater mass. After separation, gravitational forces are used to pour off the red cells. Inefficiency and problems inherent in this method arise from the conventional use of the vinyl or other flexible containers used to store blood solutions. The surface tension between the blood solution and the surface of vinyl or other flexible material used in the container results in an effect referred to as an hourglass effect whereby the flow of liquid from the volume of fluid not in contact with the interior surface of the container is faster than that along the surface itself. Where the red cells are drained off through the use of gravity, any white cells which may be disposed atop the interior volume of the red cell solution will be lost since the flow at that point will be greater than the velocity of the fluid along the container's interior surface.
The present invention substantially resolves those problems inherent in the methods and devices taught by the prior art. After separating the red and white cells through the use of conventional centrifugal equipment, the packet is inserted between a pair of clamping surfaces which are disposed along the interface of the red and white cells. Since vinyl or other flexible materials can have varying thicknesses, the clamping surfaces are maintained in a closed condition through the use of a resilient force which will automatically adjust to the thickness of the container. After the suspended cellular materials are mechanically separated through use of the container walls themselves, the white cells can be drained off from the packets without any loss thereof.